This section provides background information related to the present disclosure which is not necessarily prior art.
Electric motor assemblies commonly include a motor having a shaft for driving rotation of a component coupled to the shaft, and a motor controller, typically including a processor, for controlling operation of the motor. The motor controller may include one or more memory devices, including volatile and nonvolatile memory devices. The motor controller often uses these memory devices to store and retrieve software and data as necessary for controlling operation of the motor.
Electric motor assemblies are frequently used in systems governed by system controllers. For these applications, an electric motor assembly is typically configured to receive either a pulse width modulation (PWM) control signal or a serial communication signal from the system controller.
When a motor is controlled by a pulse width modulation (PWM) control signal, the system controller provides a signal having a constant frequency but a variable on-time and off-time. The ratio of the on-time to the sum of the on-time and off-time is the duty cycle of the PWM signal, and is often expressed as a percentage. The motor assembly, and in particular the motor controller, are typically configured to perform a certain way depending on the duty cycle of the PWM control signal.
Unlike non-communicating PWM control signals, serial communication signals can transmit a theoretically limitless amount of information to a motor assembly, including operating parameters, commands, etc. Serial communication is a bit-based communication between two or more devices and is governed by a predetermined protocol. Generally, anything that can be represented by data bits can be communicated via serial communication.